Question

（2013?張家港市模擬）某工廠常用1體積的濃硫酸（密度為1.84g?cm^-3，溶質(zhì)的質(zhì)量分?jǐn)?shù)為98%）和7體積蒸餾水混合來(lái)配制稀硫酸，所得稀硫酸中溶質(zhì)的質(zhì)量分?jǐn)?shù)最接近于（　�。�

A．10%

B．15%

C．20%

D．25%

Answer 1

分析：根據(jù)溶液稀釋前后，溶質(zhì)的質(zhì)量不變，利用m=ρV、溶質(zhì)質(zhì)量=溶液質(zhì)量×溶質(zhì)的質(zhì)量分?jǐn)?shù)進(jìn)行分析解答．

解答：解：設(shè)配制稀硫酸的溶質(zhì)的質(zhì)量分?jǐn)?shù)為x，濃硫酸的體積為VmL，蒸餾水為7VmL，則
VmL×1.84g/cm³×98%═（VmL×1.84g/cm³+7VmL×1g/cm³）×x
解得x≈20%
故選C．

點(diǎn)評(píng)：本題難度不大，掌握溶質(zhì)質(zhì)量分?jǐn)?shù)的有關(guān)計(jì)算并能靈活運(yùn)用是正確解答本題的關(guān)鍵．